. Precious stones, a popular account of their characters, occurrence and applications, with an introduction to their determination, for mineralogists, lapidaries, jewellers, etc. With an appendix on pearls and coral. Precious stones; Pearls; Corals. QUARTZ (AGATE): ARTIFICIAL COLOURING 523 in an aqueous solution of honey or sugar in a perfectly clean and new pot. The whole is kept at a temperature below boiling-point for two or three weeks, during which time the loss of water by evaporation must be made good in order to keep the stones covered with liquid. The stones are then taken out, washed


. Precious stones, a popular account of their characters, occurrence and applications, with an introduction to their determination, for mineralogists, lapidaries, jewellers, etc. With an appendix on pearls and coral. Precious stones; Pearls; Corals. QUARTZ (AGATE): ARTIFICIAL COLOURING 523 in an aqueous solution of honey or sugar in a perfectly clean and new pot. The whole is kept at a temperature below boiling-point for two or three weeks, during which time the loss of water by evaporation must be made good in order to keep the stones covered with liquid. The stones are then taken out, washed, and placed in another pot with commercial sulphuric acid (oil of vitriol) and again warmed. The honey or sugar absorbed by the stone dui-ing its immersion in the first liquid is decomposed by the sulphuric acid with Fig. 92. Antique Please note that these images are extracted from scanned page images that may have been digitally enhanced for readability - coloration and appearance of these illustrations may not perfectly resemble the original Bauer, Max, 1844-1917; Spencer, Leonard James, 1870- tr. London, C. Griffin and Company, Ltd.


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Keywords: ., bookcentury1900, bookdecade1900, booksubjectpreciousstones, booky